This invention relates generally to electrophotographic copying machines and more particularly, provides an electrophotographic copying machine formed as an assembly of self-contained modules removably mounted in a cabinet, each module containing a particular functional system of the machine.
Electrophotographic copying machines are well known in the art. Generally speaking, these machines include an electrophotographic member which is transported past or through a plurality of stations, each of which performs a functional operation of the reproducing procedure. The electrophotographic member can be constructed in the form of a drum, a plate or an endless belt. For high speed applications, it has been found advantageous to employ an electrophotographic member in the form of an endless belt mounted on rollers and to expose the belt to an image of the document to be copied at a location where the belt is in a flat condition.
The work stations generally include a charging station at which a uniform charge is applied to the photoconductive surface of the electrophotographic member; an exposure or imaging station at which the charged photoconductive surface is exposed to a light image of the document to be copied creating thereby a latent electrostatic image; a developing or toning station at which the latent electrostatic image is developed or made visible through the application of finely divided, charged toner particles that adhere to the photosensitive surface in a configuration defined by the latent electrostatic image; a transfer station at which the developed image is transferred to a secondary carrier medium such as paper and a fixing station at which the transferred image is affixed permanently to the secondary carrier medium.
In some machines, additional work stations are included, such as a cleaning station for removing residual toner from the electrophotographic member prior to reuse. In other machines one or more of the above work stations are omitted. For example, the transfer station can be eliminated and the toned image is permanently fixed onto the electrophotographic member which then becomes the final copy.
Little attention has been directed to the overall construction and assembly of the copying machine.
Generally, each of the functional operating work stations has been assembled with the others as individually mounted elements mounted fixedly either on the principal frame of the machine or to some supporting structure secured to said frame. The final assembly is performed of necessity in situ at installation of the machine where the machine is built up from "scratch" from a plurality of individual parts. Once assembled, the compulsory attendance of a skilled serviceman at the place of installation is mandatory. This involves considerable expense as well as delay in effecting repairs. Repairs must be made at the site. The machine cannot be dismantled with the defective section withdrawn and removed for service at a central location with a substitute operating section installed in place so that the machine can be operated during the duration of repairs, etc. Down-time during awaiting of service and the pendency of repairs is of considerable disadvantage.
Considerable need has arisen for the provision of an essentially modular machine comprising plural self-contained units or modules preassembled and installable to construct the machine. Not only can expenses involved in construction and installation be materially reduced, but the in situ assembly of the multitudinous parts for installation of the machine does not involve a practical assembly of each and all of the functional or operational systems from "scratch" at the installation site. Provision of modular units additionally simplifies repair with minimum down-time by permitting withdrawal of the defective module and replacement thereof by a properly operating module on site. The defective module can be transported to a service center rather than requiring on site repair by the skilled serviceman. With a modular system, even the operation of the machine can make the substitution.
Advances in copier technology have been rapid with development of new specifically functional operational systems. A machine may become obselete in short order. A modular system would enable substitution of improved functional systems into an established, i.e. older, machine and thus extend the useful life of the machine.
Insofar as applicant is aware, modular systems of the type referred to have not been developed, notwithstanding their likely advantage and utility.